Functional Assay
A functional assay is a laboratory test designed to evaluate whether a biological component (such as a gene, protein, or cell) performs its expected biological function under defined experimental conditions.
Definition
A functional assay is used to assess the activity, behavior, or performance of a biological molecule or system, often to determine its role in health or disease.
It measures what the component does, not just what it is.
Common Applications
- Determining the effect of genetic variants (e.g. VUS)
- Testing enzyme activity
- Evaluating drug responses in vitro
- Measuring cell proliferation, apoptosis, or migration
- Assessing receptor signaling capacity
Examples
| Target | What It Tests | Example |
|---|---|---|
| Enzyme | Catalytic activity | ATPase assay for energy metabolism |
| Receptor | Signal transduction | G-protein coupled receptor activation |
| Gene variant | Transcriptional regulation | Luciferase reporter assay |
| Cell | Proliferation/apoptosis/migration | MTT assay, scratch wound healing test |
Importance
Functional assays are essential in:
- Interpreting the clinical relevance of mutations
- Validating therapeutic targets
- Exploring mechanisms of disease
- Confirming biological activity of recombinant or engineered molecules